The overall goal of this career development plan is to establish an independent research program in the epidemiology of obesity in children at the University of Rochester School of Medicine. Prevalences of overweight and obesity are rising in the United States, especially among females of low socioeconomic status and racial/ethnic minorities. Pregnancy has been described as a life event in which excessive weight can be gained and subsequently retained. Thus, research and training activities will concentrate on the identification of the independent and joint determinants of gestational weight gain and post-partum weight retention in adolescents and young adults of different racial/ethnic groups as major determinants of overweight and obesity in women. The specific aims are: 1) To establish a systematic training program in adolescent nutrition and behavior, special nutritional needs of pregnant adolescents, measurement of nutritional status in pregnant and non-pregnant adolescents, statistical analysis of longitudinal and multi-level data, and measurement and analysis of community-level variables; 2) To analyze cross-sectional and longitudinal data on biological, sociodemographic, behavioral, and community-level determinants of pregnancy weight gain and post-partum weight retention m women from the New York State Regional Perinatal Data System and the Coronary Artery Risk Development in Young Adults study (CARDIA); 3) To design an observational prospective study of adolescents and young adults to identify the biological, behavioral, sociodemographic, psychological, and community-level determinants of pregnancy weight-gain and post-partum weight retention among racial/ethnic minorities. The proposed career development activities involve training in the measurement and interpretation of body composition; in reproductive, behavioral/mental health, and nutrition and healthy lifestyle issues in adolescents; in Responsible Conduct of Research; and in longitudinal and qualitative data analysis. At the end of the training program, the candidate will be an independent investigator in the field of pediatric nutrition epidemiology. The clinical and public health significance of this proposal are based on a report from the Institute of Medicine suggesting that African-American women and adolescents gain in the upper end of the recommended weight-gain during pregnancy, a warning in the literature as to the health risks to young adolescents of retaining weight gained during pregnancy, and a national goal of reducing health disparities among Americans. In addition, there is a scarcity of empirical longitudinal data on the differential determinants of pregnancy weight-gain and post-partum weight retention in adolescents of various socioeconomic and racial/ethnic minorities. Examining biological, sociocultural, and community-level factors that may differ among specific population subgroups becomes relevant in order to tailor strategies which prevent post-partum weight retention without threatening either the mother's or the newborn's health. Given the adverse health effect of obesity and the difficulties involved in maintaining weight loss, primary prevention of obesity is of particular public health importance.